A radio telescope has a parabolic surface, as shown below.
If the telescope is 1 m deep and 12 m wide, how far is the focus from the vertex? (5 points)
Answers
so.. "p" is the distance from the vertex to either, the focus point or the directrix.
thus the focus is "p" units from the vertex.
now, if we set the parabola at the origin, like in the picture, and then use another point on the parabola, let's say we'll use (6,1), then
[tex]\bf \textit{parabola vertex form with focus point distance}\\\\ \begin{array}{llll} (y-{{ k}})^2=4{{ p}}(x-{{ h}}) \\\\ \boxed{(x-{{ h}})^2=4{{ p}}(y-{{ k}})} \\ \end{array} \qquad \begin{array}{llll} vertex\ ({{ h}},{{ k}})\\\\ {{ p}}=\textit{distance from vertex to }\\ \qquad \textit{ focus or directrix} \end{array}\\\\ -------------------------------\\\\[/tex]
[tex]\bf \begin{cases} h=0\\ k=0 \end{cases}\implies (x-0)^2=4p(y-0)\implies x^2=4py \\\\\\ \begin{cases} x=6\\ y=1 \end{cases}\implies (6)^2=4p(1)\implies \cfrac{6^2}{4}=p\implies \cfrac{36}{4}=p\implies 9=p[/tex]
For a parabolic dish, the focus is at a depth equal to one-fourth of the square of the width of the dish's aperture. Given the width as 12m, the focus of the radio telescope is 36m from the vertex.
Explanation:For a parabolic dish like a radio telescope, the focus (or focal point) is located at the depth equal to one-fourth of the square of the width (i.e., one-fourth of the square of the diameter) of the dish's aperture.
Given the width (diameter) of the dish is 12 meters, we square it to get 144. Quarter of this value is 36 m. So, the focus is 36 m from the vertex of the parabola represented by the dish's surface.
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Related Questions
Which sentence best describes the independent and dependent variables in the following problem? The parking garage charges $3 for the first hour of parking and $1.45 for each additional hour.Which sentence best describes the independent and dependent variables in the following problem? The parking garage charges $3 for the first hour of parking and $1.45 for each additional hour.
Answers
The dependent variable is the additional charge applied for each hour whereas the independent variable is the charge to be applied on the first hour
The dependent variable would be $1.45 for each additional hour. The cost depends on every hour so we can't really calculate it unless we have the hours given.
$3 is independent since it's only charged on the first hour. It doesn't depend on any other information.
Which sentence best describes the independent and dependent variables in the following problem? The parking garage charges $3 for the first hour of parking and $1.45 for each additional hour.Which sentence best describes the independent and dependent variables in the following problem? The parking garage charges $3 for the first hour of parking and $1.45 for each additional hour.
Can anyone help me solve a trigonomic identity problem and also help me how to do it step by step?
it's ((cos theta) * (cot theta))/(1-sin theta) - 1 = csc theta
Answers
[tex]\bf \cfrac{cos(\theta )cot(\theta )}{1-sin(\theta )}-1=csc(\theta )\\\\ -------------------------------\\\\ \cfrac{cos(\theta )\cdot \frac{cos(\theta )}{sin(\theta )}}{1-sin(\theta )}-1\implies \cfrac{\frac{cos^2(\theta )}{sin(\theta )}}{\frac{1-sin(\theta )}{1}}-1\implies \cfrac{cos^2(\theta )}{sin(\theta )}\cdot \cfrac{1}{1-sin(\theta )}-1 \\\\\\ \cfrac{cos^2(\theta )}{sin(\theta )[1-sin(\theta )]}-1\implies \cfrac{cos^2(\theta )-1[sin(\theta )[1-sin(\theta )]]}{sin(\theta )[1-sin(\theta )]}[/tex]
[tex]\bf \cfrac{cos^2(\theta )-1[sin(\theta )-sin^2(\theta )]}{sin(\theta )[1-sin(\theta )]}\implies \cfrac{cos^2(\theta )-sin(\theta )+sin^2(\theta )}{sin(\theta )[1-sin(\theta )]} \\\\\\ \cfrac{cos^2(\theta )+sin^2(\theta )-sin(\theta )}{sin(\theta )[1-sin(\theta )]}\implies \cfrac{\underline{1-sin(\theta )}}{sin(\theta )\underline{[1-sin(\theta )]}} \\\\\\ \cfrac{1}{sin(\theta )}\implies csc(\theta )[/tex]
How can I use context clues and keywords to translate situations into inequalities? Explain with an example of your own.
Answers
Mira and Lola are looking to hire a hall for their 18th birthday party. They are expecting at least 50 guests and want a hire that will accommodate the party. Write this requirement as an inequality
Solution: the keyword here is 'at least' because it means that the hall must be able to accommodate a minimum of 50 people. It is a clue that Mira and Lola are expecting more than 50 guests. The inequality symbol for this context is 'more than or equal to' and as inequality, we have x ≥ 50
To translate situations into inequalities, use context clues and keywords. Start by understanding the relationships and factors involved. Then, represent the situation with variables and create an inequality based on the context clues. For example, if Bob earns $10 more than Alice, the inequality would be 'a < a + 10'.
Explanation:In order to use context clues and keywords to translate situations into inequalities, it's important to understand the relationships and factors involved. Let's take an example:
Scenario: Suppose you have two friends, Bob and Alice. Bob earns $10 per hour more than Alice. In this case, we can use the following context clues:
The relationship between Bob and Alice: Their wealth is unequal.The factor involved: The difference in their earnings.We can now translate this situation into an inequality:
Let's say Alice's earnings are represented by 'a'.Bob's earnings would be 'a + 10' (since he earns $10 more).The inequality can be represented as 'a < a + 10' (Alice's earnings are less than Bob's earnings).By using the context clues and the keywords (earnings, difference), we were able to translate the situation into the inequality 'a < a + 10'.
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A turkey was cooked at 300 f in the oven for 5 hours. the internal temperature rose from 35 f to 150 f. what was the average rise in temperature per hour
Answers
find the solution x-4y=9 and x-y=-9
Answers
see picture for solution
what is 475% of 9.2?
Answers
Find the area of sector AOB. Express your answer in terms of pi and rounded to the nearest tenth.
Answers
To find the area of sector AOB, use the formula A = (θ/360) * π * r^2, where θ is the angle of the sector in degrees and r is the radius. In this case, the angle θ is given as 1.11 and the radius is given as 4.5. Plugging these values into the formula, the area is approximately 0.139 m², rounded to the nearest tenth.
Explanation:To find the area of sector AOB, we need to use the formula for the area of a sector: A = (θ/360) * π * r^2, where θ is the angle of the sector in degrees and r is the radius. In this case, the angle θ is given as 1.11 and the radius is given as 4.5. Plugging these values into the formula, we get A ≈ (1.11/360) * π * (4.5)^2.
Using a calculator, we can calculate the value to be approximately 0.139 m². Rounding to the nearest tenth, the area of sector AOB is 0.1 m².
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The areas of the sectors of circles 5 and 6 to the nearest tenth are 197.8 cm² and 6.3 ft² respectively.
What are the areas of the sectors?The area of the sector of a circle can be expressed as:
Area = ( θ/360º ) × πr²
Where θ is the sector angle in degrees, R is the radius of the circle, and π is constant pi.
For question5)
Angle θ = 70 degrees
Radius r = 18 cm
Area =?
Area = ( θ/360º ) × πr²
Plug in the values:
Area = ( 70/360º ) × π × 18²
Area = 63π cm²
Area = 197.8 cm²
For question 6)
Angle θ = 180 degrees
Diameter d = 4ft
Radius r = 4/2 = 2ft
Area =?
Area = ( θ/360º ) × πr²
Plug in the values:
Area = ( 180/360º ) × π × 2²
Area = 2π ft²
Area = 6.3 ft²
Therefore, the area of the sector is 6.3 ft².
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A home pregnancy test is not always accurate. suppose the probability that the test indicates that a woman is pregnant when she actually is not is 0.02, and the probability the test indicates that a woman is not pregnant when she really is, is 0.03. assume that the probability that a woman who takes the test is actually pregnant is 0.7. what is the probability that a woman is pregnant if the test yields a not pregnant result?
Answers
T=tests positive~T=tests negativeP=subject is pregnant~P=subject is not pregnant
We are givenP(T n ~P)=0.02P(~T n P)=0.03P(P)=0.7
recall by definition of conditional probabilityP(A|B)=P(A n B)/P(B)
Need to find P(P|~T)
First step: make a contingency diagram of probabilities (intersection, n)
P ~P sum
T 0.67 0.02 0.69=P(T)
~T 0.03 0.28 0.31=P(~T)
sum 0.70 0.30 1.00
=P(P) =P(~P)
therefore
P(P|~T)=P(P n ~T)/P(~T)=0.03/0.31 [ both read off the contingency table ]
=0.0968
The probability of a woman being pregnant if a home pregnancy test yields a negative result can be calculated using conditional probabilities and Bayes' theorem. From the provided probabilities, we can substitute into Bayes' theorem to calculate this probability.
Explanation:The subject of this question is based on conditional probabilities. From the question we know that:
The probability of the test indicating a woman is pregnant when she's not (false positive) is 0.02 i.e., P(Positive|Not Pregnant) = 0.02 The probability of the test indicating a woman is not pregnant when she actually is (false negative) is 0.03 i.e., P(Negative|Pregnant) = 0.03 The probability that a woman who takes the test is actually pregnant is 0.7 i.e., P(Pregnant) = 0.7
From the above, we can find the probability of a woman being pregnant even though the test results are negative. To find this we need to use Bayes' theorem, which states:
P(A|B) = P(B|A) * P(A) / P(B)
So, to calculate the probability of a woman being pregnant given a negative test result P(Pregnant|Negative), we need the probability of getting a negative result when pregnant P(Negative|Pregnant), the probability of a woman actually being pregnant P(Pregnant), and the total probability of getting a negative test result P(Negative).
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Find the area under the standard normal curve between z = −2.57 and z = 1.27. Round your answer to four decimal places, if necessary.
Answers
P(Z ≤ 1.27) = 0.8980
P(Z ≤ -2.57) = 1 - P(Z ≤ 2.57) = 1 - 0.99488 = 0.00512
P(-2.57 ≤ Z ≤ 1.27) = 0.8980 - 0.00512 = 0.89288
0.8929 (4 d.p.)
The area under the standard normal curve between z = −2.57 and z = 1.27 is, 0.8929
What is meant by Probability?The term probability refers to the likelihood of an event occurring. Probability means possibility. It is a branch of mathematics that deals with the occurrence of a random event. The value is expressed from zero to one.
We have to give that,
To find the area under the standard normal curve between z = −2.57 and z = 1.27.
Now, the area under the standard normal curve is between z = −2.57 and z = 1.27 is,
P(-2.57 ≤ Z ≤ 1.27) = P(Z ≤ 1.27) - P(Z ≤ -2.57)
Since, P(Z ≤ 1.27) = 0.8980
And, P(Z ≤ -2.57) = 1 - P(Z ≤ 2.57)
= 1 - 0.99488
= 0.00512
Hence,
P(-2.57 ≤ Z ≤ 1.27) = 0.8980 - 0.00512
= 0.89288
= 0.8929
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HELP!! A spherical ball just fits inside a cylindrical can, 16 centimeters tall, with a diameter of 16 centimeters. Which expression gives the volume of the sphere in cubic centimeters?
Answers
formula for volume of a sphere is V=4/3 x pi x R63
if diameter = 16 than radius = 16/2 = 8
so the equation would be 4/3 x pi x 8^3
Find the area of a triangle with legs that are: 15mm,10mm,20mm
Answers
Area=sqrt(s(s-a)(s-b)(s-c))
where:
s=(a+b+c)/2
thus,
s=(15+10+20)/2
=22.5
hence the area will be:
Area=sqrt(22.5(22.5-15)(22.5-10)(22.5-20))
Area=sqrt(22.5*7.5*12.5*2.5)
=sqrt5273.4375
=72.62 mm^2
The area of a triangle with legs that are 15 mm, 10 mm, and 20 mm is [tex]72.618 mm^{2}[/tex]
Further Explanation;Area Area is a measure of how much space is occupied by a given shape. Area of a substance is determined by the type of shape in question.For example;
Area of a rectangle is given by; Length multiplied by width Area of a circle = πr². where r is the radius of a circle, Area of a square = S², Where s is the side of the square.etc.Area of a triangle The area of a triangle is given based on the type of the triangle in question.Right triangle.The area of a right triangle is given by;= 1/2 x base x height
Scalene triangleIt is a triangle that with sides and angles that are not equal.Area of a scalene triangle depends on the features of the triangle given.For example;
Sine FormulaArea of a triangle = 1/2 ab sin θ, when given two sides of the triangle and the angle between themHeron's formulaArea of a triangle = [tex]\sqrt{s(s-a)(s-b)(s-c)}[/tex] when given all the sides of the triangle. where [tex]s =\frac{(a+b+c)}{2}[/tex]In this case we are given, a = 15 mm, b = 10 mm, c = 20 mm
Therefore, we use the Heron's formula;
Area= [tex]\sqrt{s(s-a)(s-b)(s-c)}[/tex]
[tex]s =\frac{(a+b+c)}{2}[/tex]
[tex]s= \frac{(15+10+20)}{2} \\s= 22.5[/tex]
Therefore;
Area = [tex]s\sqrt{s(s-a)(s-b)(s-c)}[/tex]
= [tex]22.5\sqrt{22.5(22.5-15)(22.5-10)(22.5-20)}[/tex]
=[tex]\sqrt{22.5(7.5)(12.5)(2.5)} \\\sqrt{5273.4375}[/tex]
[tex]= 72.618 mm^{2}[/tex]
Keywords: Area, Area of a triangle, Heron's formula, Sine formula, Scalene triangle.
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Subject; Mathematics
Topic: Area
Sub-topic: Area of a triangle
Gabrielle's age is three times Mikhail's age. The sum of their ages is 44. What is Mikhail's age?
Answers
m=micsdjfsdf's age
g=3m
sum is add
g+m=44
subsitute 3m for g
3m+m=44
4m=44
divide by 4 both sides
m=11
mikhail is 11 year old
Need help with this word problem
Answers
notice, we get -10 and 8, well, it cannot be a negative value, since it's the unit of a dimension.
so, the width is (1/2)x and the height is x+2.
If prices Increase at a monthly rate of 2.3%, by what percentage do they increase in a year?
Answers
The calculation would be (100%+2.3%)^12= 131.37344984%
That would be about 31.37% a year.
An apple farmer has planted 0.3 of his orchard with cherry trees. The orchard is 8.59 acres in size. How many acres are planted with cherry trees
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Find the area of the shaded region below. The units are in feet.
Use 3.14 for π. Round your answer to two decimal places.
Answers
so.. simply, get the area of the two circles, with radius of 4, we did that, and get the area of the larger circle with radius of 8, we did that.
now... keep in mind that, the area of the larger circle, includes the area of the two smaller circles, if you subtract the area of the two smaller circles from the larger's one, you're in effect making a hole in the larger circle, and what's leftover, is the shaded region.
Of the books in a library, 1/3 came from Robbie's collection and 15 came from Marta's. Of the rest, 15 were Elena's 1/5 were Winfield's, and 5 were purchased from the bookstore. How many book are there in the library?
Answers
Robbie: r=(1/3)l
Martha: m=15
rest of books: l-r-m=e+w+b
Elena: e=15
Winfield: w=1/5(e+w+b)
bookstore: b=5
w=(e+w+b)/5
w=(15+5+w)/5
w=4+w/5
(4/5)w=4
w=5
l-r-m=e+w+b
l-(1/3)l-15=15+5+5
(2/3)l=25+15
(2/3)l=40
l=60=amount of books
The total number of books in the library are 75.
What is an equation?
The definition of an equation in algebra is a mathematical statement that demonstrates the equality of two mathematical expressions. For instance, the equation 3x + 5 = 14 consists of the two expressions 3x + 5 and 14, which are separated by the 'equal' sign.
What will be the equation for given scenario?Let the total number of books in the library be x.
The equation formed by using given information will be [tex]\frac{x}{3} +15+15+\frac{x}{5}+ 5=x[/tex]
Collect the like terms,
[tex]\frac{x}{3} +35+\frac{x}{5}=x[/tex]
On solving the equation for x we get x=75.
Therefore, the total number of books in the library are 75.
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Explain how you can use place value patterns to describe how 50 and 5000 compare
Answers
The place values in the pattern are: ones, tens (10*ones), hundreds (10*tens), thousands (10*hundreds),...
So, 50 = 5 tens
5000= 5 thousands, 0 hundreds, 0 tens, 0 ones
So, 5000 > 50
Multiply and Dividing Rational Numbers
8/9 ÷ 2/3
7/8 × 1/4
3/4×1/6
Answers
[tex]\bf \cfrac{8}{9}\div \cfrac{2}{3}\implies \cfrac{8}{9}\cdot \cfrac{3}{2}\implies \cfrac{8\cdot 3}{9\cdot 2}\implies \cfrac{24}{18}\implies \cfrac{4}{3} \\\\\\ \cfrac{7}{8}\cdot \cfrac{1}{4}\implies \cfrac{7\cdot 1}{8\cdot 4}\implies \cfrac{7}{32} \\\\\\ \cfrac{3}{4}\cdot \cfrac{1}{6}\implies \cfrac{3\cdot 1}{4\cdot 6}\implies \cfrac{3}{24}\implies \cfrac{1}{8}[/tex]
A pharmacist has 40% and 80% iodine solutions on hand .How many liters of each iodine solutions will be required to produce 6 liters of a 50% iodine mixture?
Answers
[tex]\bf \begin{array}{lccclll} &amount&concentration& \begin{array}{llll} concentration\\ amount \end{array}\\ &-----&-------&-------\\ \textit{40\% sol'n}&x&0.4&0.4x\\ \textit{80\% sol'n}&y&0.8&0.8y\\ -----&-----&-------&-------\\ mixture&6&0.5&3 \end{array}[/tex]
so... whatever "x" and "y" may be, we know the must add up to 6 liters.
and whatever 0.4x and 0.8y are, we also know, they must add up to a 3 of concentrated amount.
thus [tex]\bf \begin{cases} x+y=6\implies \boxed{y}=6-x\\ 0.4x+0.8y=3\\ ----------\\ 0.4x+0.8\left( \boxed{6-x} \right)=3 \end{cases}[/tex]
solve for "x", to see how much of the 40% solution will be needed.
what about "y"? well, y = 6 - x.
PLEASE HELP WITH SOME GEOMETRY
Prove the following statement by contradiction using an indirect proof. In a triangle angle A = 90°, then the triangle is a right triangle. Which of the following choices would be the first step to temporarily assume?
angle A = 90°
the triangle is a right triangle
the triangle is not a right triangle
angle A is not 90°
Answers
"The triangle is not a right triangle angle and A is not 90°"
Then you proof that this statement is false
A company uses a variable percentage markup of 35% .if the total cost of a product is $15,what is its selling price
Answers
The selling price of a product with a 35% markup on a cost of $15 is calculated by adding the markup amount of $5.25 to the cost, resulting in a selling price of $20.25.
Explanation:To calculate the selling price of a product using a variable percentage markup, you first need to determine the amount of markup by converting the percentage to a decimal and multiplying by the cost of the product. In this case, with a 35% markup on a product that costs $15, the calculation is as follows:
$15 × 0.35 = $5.25
This $5.25 represents the amount of markup on the product. To find the selling price, you simply add the markup to the cost:
$15 + $5.25 = $20.25
Therefore, the selling price of the product would be $20.25.
jim sold 200 litters of soda at baseball game.How much is this in milliters?
Answers
1000 * 200 = 200000
So, 200000 milliliter is the answer.
One liter is 1000 milliliters. To convert between them, multiply 200 by 1000 to get 200,000
True or false: the difference between the lower limit of a confidence interval and the point estimate used in constructing the confidence interval is called the sampling error.
Answers
Sampling error is an error which is calculated by finding the difference between the lower limit or upper limit of a confidence interval and the point estimate used in constructing the confidence interval.
As we can calculate the difference, so sampling error can be positive or negative.
Name the three different types of proof in math and give a description of each
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2/3 of a number is 32, what is the number?
Answers
a=32×3/2
a=96/2
a=48
The number is 48
Integers:- 3/2•2/3 = 32/1 = 3/2 = 96/2 = 48
Which quantity is proportional to 20/5?
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amy has 72 sweets in bag.she keeps 1/4 of them for herself,but shares the remainder between 6 of her friends.how many sweets will she give to each of her friends?
Answers
she has 54 left to share
54 divided by 6 is how many sweets each friend will get
Each friend gets 9 sweets
A study of sleep patterns randomly selected participants in the study to sleep in either a dark room or a room with light.
Which element of experiment design is known to be a part of this study?
A.
blinding
B.
replication
C.
randomization
Answers
Answer:
C. randomization
Step-by-step explanation:
We are told that the study randomly selects participants in the study to sleep in either a dark room or a room with light. This means that randomization is part of the study.
You draw two cards from a standard deck of 52 cards without replacing the first one before drawing the second. find the probability that the first card is an ace and that the second card is an ace?
Answers
4 aces in a deck
52 cards
you have a 4/52 reduced to 1/13 probability of picking an ace.
without replacing it there would be 51 cards left and 3 aces
so second probability of picking an ace is 3/51 reduced to 1/17
the probability of doing both = 1/13 x 1/17 = 1/221
Answer:
conf
Step-by-step explanation: